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* objtool warning for wanxl_pci_init_one with gcc-7
@ 2017-01-04 11:19 Arnd Bergmann
  2017-01-06 17:34 ` Josh Poimboeuf
  0 siblings, 1 reply; 2+ messages in thread
From: Arnd Bergmann @ 2017-01-04 11:19 UTC (permalink / raw)
  To: Josh Poimboeuf; +Cc: linux-kernel

Hi Josh,

I'm getting a new warning with the latest gcc-7 snapshot, I think this
is a false positive:

drivers/net/wan/wanxl.o: warning: objtool: wanxl_pci_init_one()+0x9d2: sibling call from callable instruction with changed frame pointer

# /git/arm-soc/drivers/net/wan/wanxl.c:133:     switch((value >> STATUS_CABLE_PM_SHIFT) & 0x7) {
        movl    %eax, %ecx      # value, _314
        movl    %eax, %r10d     # value, _224
        movq    (%r15), %rdi    # MEM[base: _546, offset: 0B], pretmp_490
        shrl    $5, %ecx        #, _314
        andl    $8, %r10d       #, _224
        movl    %ecx, %edx      # _314, tmp377
        andl    $7, %edx        #, tmp377
        jmp     *(%r14,%rdx,8)  #
        .section        .rodata
        .align 8
        .align 4
.L280:
        .quad   .L278
        .quad   .L278
        .quad   .L279
        .quad   .L281
        .quad   .L282
        .quad   .L305
        .quad   .L278
        .quad   .L306
        .text

	Arnd

^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: objtool warning for wanxl_pci_init_one with gcc-7
  2017-01-04 11:19 objtool warning for wanxl_pci_init_one with gcc-7 Arnd Bergmann
@ 2017-01-06 17:34 ` Josh Poimboeuf
  0 siblings, 0 replies; 2+ messages in thread
From: Josh Poimboeuf @ 2017-01-06 17:34 UTC (permalink / raw)
  To: Arnd Bergmann; +Cc: linux-kernel

On Wed, Jan 04, 2017 at 12:19:20PM +0100, Arnd Bergmann wrote:
> Hi Josh,
> 
> I'm getting a new warning with the latest gcc-7 snapshot, I think this
> is a false positive:
> 
> drivers/net/wan/wanxl.o: warning: objtool: wanxl_pci_init_one()+0x9d2: sibling call from callable instruction with changed frame pointer
> 
> # /git/arm-soc/drivers/net/wan/wanxl.c:133:     switch((value >> STATUS_CABLE_PM_SHIFT) & 0x7) {
>         movl    %eax, %ecx      # value, _314
>         movl    %eax, %r10d     # value, _224
>         movq    (%r15), %rdi    # MEM[base: _546, offset: 0B], pretmp_490
>         shrl    $5, %ecx        #, _314
>         andl    $8, %r10d       #, _224
>         movl    %ecx, %edx      # _314, tmp377
>         andl    $7, %edx        #, tmp377
>         jmp     *(%r14,%rdx,8)  #
>         .section        .rodata
>         .align 8
>         .align 4
> .L280:
>         .quad   .L278
>         .quad   .L278
>         .quad   .L279
>         .quad   .L281
>         .quad   .L282
>         .quad   .L305
>         .quad   .L278
>         .quad   .L306
>         .text

Thanks Arnd, will take a look at it.  This reminds me that I need to
ping the gcc guys about better annotations of switch statement jump
tables.

-- 
Josh

^ permalink raw reply	[flat|nested] 2+ messages in thread

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